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I need help in "transcription" of my logs to get understanding what's going on :)
Brief inro: full stock Celica Gt-Four (st185) with installed AEM Logger and Greddy e-01 boost-controller (it was in boost-off mode during session). I've wired signals from MAF, RPM, water temp, and throttle position sensors to AEM. What I was seeking:
The car has poor acceleration and "jerks" when I actively press a throttle. There are two cases here:
- when I press to WOT or ~50%-70 nothing happens, then the car starts to accelerate slowly, got "jerking" at ~2000-2500 RPM then stabilizes and accelerates normally.
- when I press throttle gently, the car accelerates more or less smoothly
I've got logs, here is a sample of case No 1.
My questions are:
1. Is MAF (as you can know, st185 has VAF-type actually) signal jittered because of jittered RPM (by some unknown reason) or MAF signal actually causes RPM jitter? I can't understand what I see :) (Screenshot_6.png)
2. Why RPM can be so "noisy" at high levels? (Screenshot_6.png)
3. What is this? I can't understand this plateau while RPM is dropping and the throttle is fully closed. (Screenshot_7.png)
Thanks a lot!
Alexander normally when i have seen this it is from retarded ignition timing
my sugestion would be to check the base timing and check the ignition advance is also working correctly.
Good point! I think that is it. I changed a distributor before that and probably set the wrong ignition timing.
Should write for the future internet archeologists :)
I've checked an ignition and it turned out that it was perfectly set by my hand (10 deg to BTDC).
Finally, I added AFR to log and distinctly saw a lean AFR at idle. st185 has a stupid 2-speed fuel pump (controlled by fuel pump relay. It switches voltage from 6v to 12v exact at 2500-3000 RPM. Throwed relay in a bin, set a jumper, and got my smooth boost. Woohoo!